In equipment for charging a liquid refrigerant into a refrigeration or air conditioning system, for example, as disclosed in U.S. Pat. No. 3,538,961 and No. 4,032,041, and particularly in equipment for charging air conditioning systems for motor vehicles on an assembly line, it is common to couple the system first to a vacuum pump unit and then to a liquid refrigerant dispensing unit. The vacuum pump is used to evacuate air from the system after which the liquid refrigerant is dispensed or charged into the system to a predetermined volume.
As disclosed in above U.S. Pat. No. 3,538,961, a suction line and a liquid refrigerant dispensing or charging line are coupled to the system with manually actuated quick-connect couplings each of which encloses a valve member or element movable from a normally closed position to an open position when the coupling is attached to a male process fitting having an internal check or stem valve and connected to the system. In more recent years, both the suction line and the refrigerant supply line are connected by a single coupling which connects with a single valve fitting on the system. The system is first evacuated through the fitting and coupling and then the liquid refrigerant is charged into the system through the fitting. The single quick-connect coupling is particularly desirable in an automotive production line since less time is required to connect and disconnect one coupling in place of two couplings.
In an automotive production line, it has been found desirable for the quick-connect coupling to be attached or connected to the process fitting with a minimum time and effort and also for the coupling to be automatically disconnected from the fitting after the system has been charged with refrigerant. It has also been found desirable for the coupling to be compact in size and to be quickly connectable to the process fitting without requiring precise alignment between the coupling and the fitting. These desirable features minimize the operator's time and eliminate the need for the operator to disconnect the coupling from the fitting at the end of the charging cycle. It has also been found important to minimize the release of refrigerant vapor or gas when the coupling is disconnected from the valve fitting.